1. Field of the Invention
This invention relates to a recording and/or reproducing apparatus which can record and/or reproduce data of a program onto or from, for example, a disk-shaped recording medium.
2. Description of the Related Art
Recordable disk media such as, for example, magneto-optical disks (MO disks) are more suitable to random accessing as compared with tape-shaped recording media such as digital audio tapes and compact cassette tapes. Various recording and/or reproducing apparatus for recording and/or reproducing such recordable disk media are already known, and an example of such a recording and/or reproducing apparatus is disclosed, for example, in U.S. patent application Ser. No. 717,700, filed Jun. 19, 1991, now U.S. Pat. No. 5,214,631, and assigned to the assignee of the present patent application. A recording and/or reproducing apparatus of the type mentioned need not necessarily record, for example, a program on a continuous segment of a recordable disk medium but may record it discretely on a plurality of segments on the disk (it is to be noted that the segment herein denotes a portion of a track in which data are recorded physically and continuously on a disk). In short, if a recording and/or reproducing operation within a segment and a high speed accessing operation are repeated, then even if a track of a program is physically divided into a plurality of segments, there is no trouble in recording and/or reproducing of the program.
For example, referring to FIG. 15, data of a first program and data of a second program are recorded continuously on a segment T.sub.1 and another segment T.sub.2. However, it is also possible to record data of a program separately on discontinuous segments in such a manner that data of fourth and fifth programs are recorded divisionally on discontinuous segments T.sub.4(1) to T.sub.4(4) and T.sub.5(1) to T.sub.5(2), respectively, as shown in FIG. 15. It is to be noted that FIG. 15 shows the disk only in a schematic fashion, and actually, in most cases one segment extends over several to several hundreds tracks.
When recording or erasure of a program onto or from a magneto-optical disk is repeated, empty areas are produced irregularly on tracks of the disk due to a difference between playing times of recorded programs or between playing times of erased programs. However, if such discrete recording is performed, then it is possible to record, for example, a program longer than another program erased from the disk onto the disk by making use of the portion from which the program has been erased. Consequently, it can be prevented that a useless data recording area is produced by a repetition of recording and/or erasure. It is to be noted that recorded information is not always data of a program (musical piece) and may be any audio signal, and accordingly, in the present specification, a mass of data continuous in contents is represented as "program".
In a disk medium of the type described above, in order to allow random accessing, data for linking segments (for example, T.sub.4(1) to T.sub.4(4) in FIG. 15) of a program are stored as user TOC (Table of Contents) information which is re-written each time a recording operation or an erasing operation is performed. Thus, a recording and/or reproducing apparatus is controlled so as to read the user TOC information and perform accessing of a head to achieve an appropriate recording and/or recording operation. An of example signal recording and/or reproducing apparatus of the type just described is disclosed in U.S. patent application Ser. No. 945,488, filed Sep. 16, 1992 and assigned to the assignee of the present patent application.
Incidently, addresses of a start position and an end position which define the range of a segment as well as link information which designates a succeeding segment to which the former segment is to be linked are recorded normally as such user TOC data for linking segments. This way, if the link information is traced, then a segment to be accessed can be grasped by the system. Consequently, even if a program is recorded divisionally in a plurality of segments, an ordinary operation such as a recording operation or a reproducing operation can be performed.
However, information designating a preceding segment from a certain segment, that is, link information in the reverse direction, is not recorded on a disk medium. Consequently, it is impossible to trace back segments based on user TOC information. Accordingly, a disk medium is disadvantageous in that it is very difficult to perform reverse reproduction, fast reverse reproduction or the like.